Challenges of sustainability of rice agrosystem: Insights from energy use, ecological footprint, and greenhouse gas emissions (case study: Golestan province, Iran)

This study assesses the energy use, ecological footprint, and greenhouse gas emissions from rice (Oryza sativa) production in Iran's Golestan province. The energy indices, greenhouse gas emissions, and ecological footprint in the rice paddies were calculated and analyzed after identifying the key inputs and outputs of these cropping systems. The energy use efficiency, energy productivity, specific energy, and net energy were measured to be 3.17, 0.19 kg MJ⁻¹, 5.30 MJ kg⁻¹, and 77,685.42 MJ ha⁻¹, respectively. Additionally, the analysis revealed that the global warming potential, net carbon, and carbon efficiency ratio were 4565.35 kg carbon dioxide equivalent (CO₂-eq) ha⁻¹, 1804.86 kg C ha⁻¹, and 2.46, respectively. The ecological footprint was measured to be 2.68 global hectares, which was more than the carrying capacity of each hectare of land allocated for crop cultivation. Hence, the environmental sustainability of rice production in the Golestan province was low. Alternatives such as rapeseed (Brassica napus) could reduce the environmental impact of rice farming in the province. Sustainability could be improved by reducing the reliance on electricity and nitrogen fertilizer that are produced using fossil fuels.